1. Field of the Invention
The present invention relates to an imprint apparatus, an imprint method, and a method of manufacturing an article.
2. Description of the Related Art
Demand for smaller semiconductor devices has increased, and in addition to conventional photolithography techniques, attention has been given to imprint technology according to which an imprint material (uncured resin) on a substrate is molded using a mold (die) so as to form a resin pattern on the substrate. Imprint technology makes it possible to form microstructures on the order of several nanometers on a substrate. Photocuring is known as one example of imprint technology.
With an imprint apparatus that employs photocuring, first, photocurable resin (e.g., ultraviolet curable resin) is applied to a shot region on a substrate, and this resin is molded using a mold. The resin is then cured by being irradiated with light (e.g., ultraviolet light), and the mold is then separated (detached), and thus a resin pattern is formed on the substrate.
This type of imprint apparatus is disclosed in Japanese Patent No. 4478424, and includes a substrate stage for positioning a substrate, an alignment substrate that is arranged on the substrate stage and includes a reference alignment mark formed thereon, and an alignment detection system, for example. The alignment detection system detects misalignment between the reference alignment mark and an alignment mark formed on the mold, for example. Alignment of the mold and the substrate can be performed based on the detection results from the alignment detection system.
However, in conventional imprint apparatuses, when detecting misalignment between the reference alignment mark and the alignment mark formed on the mold with the alignment detection system, it is necessary to bring the mold and the alignment substrate close together (i.e., reduce the gap between the mold and the alignment substrate) when detecting the alignment marks. Accordingly, if a foreign particle exists on the alignment substrate, there is a possibility of the mold becoming damaged due to coming into contact with the foreign particle (i.e., the foreign particle is sandwiched between the mold and the alignment substrate).